1. Field of the Invention
The invention relates generally to lighting fixtures configured with flux management structure for preventing light spillage, light potentially wasted as glare being redirected into a beam and onto an area to be illuminated.
2. Description of the Prior Art
Light spillage is an age-old problem encountered in the lighting field, such spillage normally producing undesirable glare. One lighting area in which such spillage is particularly onerous is the field of sports lighting. Sports lighting has evolved over time into a form of outdoor lighting having characteristics similar to outdoor area lighting yet peculiar to those requirements which come into play when lighting athletic playing fields. Uniformity of illuminance is of critical importance as is illumination level per se with these factors being joined by the ever present need for optimum performance at the lowest possible cost. Advances in the art thus occur at least in part through development of luminaire configurations which effectively deliver a maximal amount of flux onto a playing area. In the sports light field in particular both vertical and horizontal illuminances must also be addressed as must illumination levels required for optimum video camera operation inter alia. Luminaire design also typically takes into account conventional arrangements of pole locations, mounting heights and aiming angles. Other objectives include consistent overlap of beam patterns in order to maximize system performance while minimizing costly applications engineering efforts usually associated with sports lighting systems. The prior art has long encompassed the mounting of discrete clusters of sportslighting luminaires at periodic locations about the perimeter of a playing area. Within these conventional system constraints, luminaire performance is evaluated not only as a single unit but also within these discrete clusters, the net distribution of each cluster being necessarily considered in performance evaluation. As is therefore to be appreciated, luminaire design in the sportslighting field is a complex matter dependent upon a variety of factors not the least of which is total system cost.
When considering cost, operational costs cannot be dismissed as inconsequential. Prior sportslighting systems which utilize less efficient light sources such as incandescent and mercury vapor must be improved in order to gain the benefits of greater efficiency with comparable light levels and desirable light quality which are to be gained from sources such as high pressure sodium and metal halide, as examples. Greatest luminaire flexibility is attained through luminaire design capable of using the widest variety of illumination sources to include high pressure sodium and metal halide and the like.
Examples of prior art lighting designed for the purposes to which the present invention are directed are disclosed by Lemons et al in U.S. Pat. Nos. 4,864,476 and 5,313,379 and by Tickner in U.S. Pat. Nos. 5,355,290 and 5,377,086. As is conventional in the art, these patents disclose the use of reflector structures intended to provide desired illumination levels on a work plane. Sportslighting luminaires of the prior art can also be seen in the TV Sportslighting luminaire manufactured by Lithonia Lighting, a division of National Service Industries, Inc. of Atlanta, Ga., this luminaire including in its optical structure an anodized aluminum reflector capable of a range of beam spreads. The TV luminaire further includes a horizontal degree aiming scale and repositioning locator as well as a vertical aiming adjustment mechanism complete with degree aiming scale and a repositioning stop. While sportslighting luminaire devices such as the TV luminaire of Lithonia Lighting provide lighting capabilities of substantial utility and while other luminaire devices of the prior art also provide capabilities desirably useful in the sportslighting field, a need exists in the art for sportslighting luminaires capable of improved cost and energy efficiencies and which particularly provide performance capabilities allowing use of fewer luminaires within a given system arrangement.
Outdoor lighting of other description inherently exhibits many of the same problems described above relative to sportslighting, light spillage becoming glare which can be objectionable for a number of reasons not the least of which is that light wasted as glare is not brought to bear upon an area which is to be illuminated. Floodlighting applications also are illuminated by fixtures which suffer from light wasted due to spillage and glare and which can be improved as can lighting of many varying forms by the provision of a flux managing feature within the fixture which precisely pass flux nearby original arc and through a second bounce off a reflector structure to direct that flux back into beam A flux managing feature in such lighting fixtures will act to reduce glare and xe2x80x9cspillxe2x80x9d light and thus optimize performance.
The invention provides in certain embodiments luminaire structures intended for illumination of stadia, playing fields and similar areas and which are particularly adapted to mounting in discrete clusters on poles or the like at locations about the perimeter of a playing area which is to be illuminated. The luminaire structures of the invention are particularly improved in the several embodiments of the invention by reflectors which usually include a faceted reflector body with individual facets being arranged in a manner intended to optimize performance. In the several embodiments of the invention, improved principal reflectors are used in combination with an illumination source to provide an improved luminaire useful in sportslighting applications. In certain embodiments of the invention, faceted reflectors are combined according to the invention with a shielding device or flux manager and a reflector insert for optimization of light uniformity and reduction of glare and xe2x80x9cspillxe2x80x9d light. The flux manager structures of the invention produce target extinctions by management of the flux to precisely pass flux nearby original arc and through a second bounce off of the principal reflector to direct that flux back into the beam. A virtual arc is produced in proximity to the original arc with the virtual arc acting as a second source. The reflector insert is a multi-faceted reflector with aimed facets which re-direct light which would have been incident on the flux manager. One embodiment of the invention is comprised of a principal reflector having individual facets aimed in a manner to optimize uniformity of light distribution with reduced glare and light xe2x80x9cspillxe2x80x9d without the need for a flux manager and reflector insert. The several embodiments of the invention provide improved light distributions and performance of a magnitude which allows use of fewer luminaires for a given playing field configuration.
The luminaire structures of the invention typically include a ballast and junction box housing assembly having mounting trunnion arrangements with a horizontal degree aiming scale and a repositioning locator. Vertical aiming adjustment is also provided to include a degree aiming scale and a repositioning stop. Mounted to the housing assembly is one of the primary reflectors of the invention, the reflectors being sealed by a hinged lens formed of heavy-duty thermal-resistant, shock-resistant and impact-resistant tempered glass. An illumination source such as a standard BT-56 jacketed lamp is mounted within the principal reflector by a porcelain mogul-base socket in a fixed relation to the reflective surfaces of the principal reflector. The luminaire structures of the invention typically utilize high pressure sodium or metal halide lamps of wattages within the range of 400 watts to 1500 watts. A range of beam spreads are provided by the luminaire structures of the invention.
In certain other embodiments of the invention including embodiments which particularly relate to outdoor lighting, spot lighting and other types of lighting, it is to be seen that the use of a flux management feature can produce essentially the same advantages as referred to hereinabove relative to sportslighting per se. In all of these lighting applications, a flux management feature redirects light which would be wasted as xe2x80x9cspillxe2x80x9d or glare back into an illumination beam which is being directed upon an area to be illuminated. Reflector structures which can be used in these lighting applications can be faceted or can be conventional and may or may not include a reflector insert having the capability of the insert referred to hereinabove as used in sportslighting applications.
Accordingly, it is an object of the invention to provide luminaire structures capable of efficiently illuminating stadia, playing fields and similar areas with light of improved uniformity.
It is another object of the invention to provide luminaire structures intended for sportslighting applications and having improved principal reflectors formed with facets intended to optimize performance, the principal reflectors being useful with conventional illumination sources and being improved in certain embodiments to reduce light xe2x80x9cspillagexe2x80x9d by the addition of a flux manager intended to produce desired target extinctions, the flux manager creating precise redirection of flux around original arc with the redirected flux being reflected by the principal reflector into the beam, the principal reflectors used with a flux manager further being optimized by addition of a reflector insert having aimed facets which re-direct light blocked by the flux manager.
It is a further object of the invention to provide luminaire structures having improved principal reflectors and/or improved reflector assemblies capable of sufficient improvement of illumination on the work plane of a playing field to allow use of fewer luminaires for a given playing field configuration.
It is a still further object of the invention to provide luminaire structures improved to reduce light xe2x80x9cspillagexe2x80x9d by the addition of a flux management feature intended to produce desired target extinctions, the flux management feature creating precise redirection of flux around original arc with the redirected flux being reflected by a conventional reflector into a beam for illumination of a given area.
Other objects and advantages of the invention will become more readily apparent in light of the following detailed description of the preferred embodiments.